Minimally invasive medical techniques are intended to reduce the amount of tissue that is damaged during medical procedures, thereby reducing patient recovery time, discomfort, and harmful side effects. Such minimally invasive techniques may be performed through natural orifices in a patient anatomy or through one or more surgical incisions. Clinicians may insert medical tool through these natural orifices or incisions to reach a target tissue location. Medical tools include instruments such as therapeutic instruments, diagnostic instruments, and surgical instruments. To reach the target tissue location, a minimally invasive medical tool may navigate natural or surgically created passageways in anatomical systems such as the lungs, the colon, the intestines, the kidneys, the heart, the circulatory system, or the like.
Minimally invasive surgical procedures typically rely on some sort of instrument position monitoring to ensure proper access to, and behavior at, the target tissue location. Conventional minimally invasive surgical instruments are generally either formed from generally rigid, elongate elements (e.g., laparoscopic or teleoperational systems) or highly flexible systems designed to follow a predetermined anatomic path (e.g., angioplasty balloon catheters). In either case, position monitoring typically involves localized tracking of a discrete portion of the instrument (e.g., the distal tip of a catheter). The remaining guidewire/catheter length is not actively monitored, except in an incidental sense to the extent the remaining length is shown during fluoroscopic visualization of the tip advancement.
However, increasingly more complex minimally invasive surgical systems can require enhanced instrument position monitoring for safe and effective use. Navigational assist systems help the clinician route the surgical instruments and avoid damage to the anatomy. These systems can incorporate the use of shape sensors to more accurately describe the shape, pose, and location of the surgical instrument in real space or with respect to pre-procedural or concurrent images. In a dynamic anatomical system and/or in an anatomical region dense with many anatomical passageways, accurately registering the minimally invasive instrument to the anatomical system is a time consuming and processing intensive task. Improved systems and methods are needed for increasing the accuracy and efficiency of systems and methods of registering minimally invasive instruments to the anatomical system.